Dungarpur, one of the most backward districts of India, is a predominantly tribal region of Rajasthan state. Ground water is the major source of drinking water in the region. High concentrations of Fluoride (F) and Iron (Fe) have been reported in the region which poses high risk of rampant water-borne diseases. This study evaluates the ground water quality for drinking purpose in terms of 10 hydro-geochemical and two biological parameters in context of causative factors like land use and geology of the region. The occurrence of water borne diseases in resident population has been examined in association with quality of drinking water and priority areas for policy intervention have been identified. Water samples have been collected from 173 drinking water sources and 346 households consuming water from the selected sources have been surveyed for prevalence of water borne diseases. Water quality surfaces have been mapped in terms of F, Total Dissolved Solids (TDS), Hardness, Fe, alkalinity, Faecal Coliform (FC), E. Coli, and Water Quality Index (WQI) computed on the basis of 10 geochemical parameters, using Inverse Distance Weighted (IDW) method. Results reveal that the north-eastern part comprising Aspur, Sabla and part of Sagwara tehsils predominantly has ‘very poor’ to ‘unsuitable’ water quality. The western part has excessive faecal contamination. Entire district has high levels of TDS and hardness, while excessive Fe and F occur in specific regions. Disease incidence closely corresponds to the geochemical and microbial composition of water. Higher values of WQI correspond with occurrence of Phyllites and Mica Schists.